In recent years, the public (e.g., medical personnel and healthcare providers, drug addicts, drug users, and the like) has become increasingly aware of the health hazards associated with needle reuse and accidental needle prickings. For example, at least twenty blood-borne pathogens may be transmitted by the reuse of needles or accidental needle prickings. For example, these blood borne pathogens may include and are not limited to Human Immunodeficiency Virus (HIV), Acquired Immunodeficiency Syndrome (AIDS), Hepatitis B, Hepatitis C, syphilis, malaria, tuberculosis, and herpes. Despite the awareness of the risk of needle reuse and accidental needle prickings, at least 36 percent of HIV/AIDS cases and more than 50 percent of Hepatitis B and Hepatitis C cases in the United States may be linked to the sharing of needles among drug addicts. Accordingly, there is a need to curb the practice of sharing needles among drug addicts.
The problem of needle sharing or needle reuses is further amplified when viewed in relation to the world population. For example, approximately 30 percent of reported HIV/AIDS cases in Brazil, Chile, Uruguay, Paraguay and Argentina are directly related to the sharing of contaminated needles among drug addicts. Approximately 70 percent of the HIV cases reported in China are directly linked to the sharing of contaminated needles. In eastern European countries, 80 percent of injection drug addicts admit to sharing contaminated needles. Approximately 43 percent of HIV/AIDS cases reported in Poland and Yugoslavia are linked to the sharing of contaminated needles among drug addicts.
Accidental needle prickings also pose a threat to healthcare workers. In particular, approximately one million accidental needle prickings are reported by healthcare workers in the United States annually. However, it is believed that at least three million accidental needle prickings occur each year, of which about two million are unreported. Various studies estimate that out of all the accidental needle pricking injuries that occur to nurses, approximately 40 percent to 53 percent go unreported. Various studies also estimate that out of all the needle pricking injuries that occur to laboratory technicians, approximately 92 percent go unreported. Various studies further estimate that out of all the needle pricking injuries that occur to physicians, approximately 70 percent to 95 percent go unreported.
In 1997, the Center for Disease Control and Prevention (CDC) sponsored a study that found that approximately 76 percent of needle pricking injuries could be avoided by using safety needles. Presently, there are at least 250 types of safety syringes. Unfortunately, the retractable safety syringes that currently exist have been criticized for various problems associated in operating the retractable safety syringe and its ineffectiveness.
One type of safety syringe is a vacuum assisted safety syringe wherein the needle of the syringe is retracted into a syringe body after a piston engages a needle holder due to a retraction force of a variable vacuum compartment. The retraction force of the variable vacuum compartment is a function of the surface area of the piston as it is traversed from a retracted position to an engaged position. Various types of seals may be used to create an airtight barrier around the plunger shaft. The seal or seals used to produce the variable vacuum compartment may begin to break down, become less resilient, or otherwise fail over time or due to various environmental conditions. For example, when various components of a syringe, such as the seal, are exposed to a prolonged force, the components may conform to an undesirable shape thereby reducing the effectiveness of the component and hamper the overall operation and function of the syringe. Additionally, the seals, or other components, of some safety syringes are prone to react negatively to hot climates. The exposure of these syringes to hot temperatures, cold temperatures, or temperature cycling during storage or shipment can lead to an operational failure of the syringe.
Furthermore, it is often desirable to prefill a safety syringes during an automated process prior to shipment. The process of manufacturing prefilled syringes typically includes sterilizing the syringe. The prefilled and sterilized syringe may then be shipped via at least one air shipment. If the shipment of prefilled syringes is shipped a long distance, such as to a developing country, the shipment of prefilled syringes may be carried via numerous air shipments. During the air shipment of the prefilled syringe the prefilled syringe may be exposed to numerous changes in atmospheric pressures. In some cases, shipping a prefilled syringe via air may exposed the syringe to a reduced pressure equivalent to an elevation of approximately 8,000 feet. If a gas bubble is present in the fluid chamber of the syringe, the gas bubble may increase in volume due to the decreased atmospheric pressure. As the gas bubble increases in volume, the stopper of the syringe may be proximally displaced, which may ultimately cause a sterility failure in the syringe. When the syringe returns to normal atmospheric conditions, the gas bubble returns to its starting volume and the stopper will return to its original location. Thus, a visual inspection of the stopper may not indicate stopper movement has occurred and a sterility failure may have transpired during shipment.
Accordingly, there is a need in the art for an improved safety syringe.